This invention relates to a lubricating device for an outboard motor and more particularly an improved lubricant system for an outboard motor that insures proper operation even in the event that the outboard motor trim is changed.
It is well known that outboard motors frequently employ two cycle internal combustion engines. Although such engines are frequently lubricated by mixing lubricant with the fuel, recently, separate lubricating systems have been proposed wherein lubricant is supplied to the engine from a lubricant tank separate from the fuel tank. Frequently these systems employ a lubricant tank that is mounted directly in the power head of the outboard motor. As is well known, outboard motors are conventionally mounted for tilt and trim adjustment. Obviously, when the trim of the outboard motor is varied, the level of the lubricant in the power head mounted tank will change and this can, unless otherwise compensated for, adversely effect the lubrication system and its function.
It is, therefore, a principal object of this invention to provide an improved lubricating system for an outboard motor having a separate lubricant tank mounted in the power head of the outboard motor.
It is a further object of this invention to provide an improved control for the lubricating system of an outboard motor that is responsive to changes in trim that could adversely effect the operation of the lubrication system.
One very popular type of lubricating system for outboard motors is of the type shown in U.S. Pat. No. 4,572,120, entitled "Separate Lubricating System For Marine Propulsion Device", issued Feb. 25, 1986 and now reissued as RE 32,593. In the system shown in that patent, the lubricant system for the engine includes a large lubricant storage tank that is positioned externally of the outboard motor and which is mounted within the hull of the associated watercraft. This tank supplies fuel to a lubricant delivery tank that is mounted within the power head of the outboard motor and which delivers lubricant to the engine lubricating system. There is provided a float operated switch arrangement in the lubricant delivery tank that controls an electric motor driven pump for maintaining the level of lubricant within the delivery tank between predetermined minimum and maximum levels.
As noted in that patent, however, the trim adjustment of the outboard motor can cause the lubricant level to appear to be lower than it actually is. If the external pump is operated, excess lubricant can be supplied to the tank that will overflow when the trim is returned to normal. This is obviously an undesirable condition and an embodiment of that application discloses a mercury switch that is operative to prevent such overfilling conditions. Such mercury level switches must, however, be adjusted for each type of outboard motor and its pivot arrangement. This is unduly complicated.
It is, therefore, a still further object of this invention to provide an improved arrangement for controlling the operation of a lubricant system to compensate for situations when the trim of the outboard motor is changed sufficiently to require correction of the operation of the lubricating system.
It is a further object of this invention to provide an improved lubricating system that incorporates a trim condition mechanism that controls the lubrication system when the trim condition is changed to one in which the lubricating system requires control.